JP3687567B2 - High frequency heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high frequency heating apparatus that dielectrically heats an object to be heated using high frequency energy.
[0002]
[Prior art]
A conventional high-frequency heating apparatus is mainly configured to uniformly heat an object to be heated, and includes a turntable mechanism that rotates the object to be heated, a stirrer mechanism that stirs high-frequency waves in the heating chamber with radio wave reflecting blades, or Japanese Patent Publication No. 1-48629. And a rotating waveguide mechanism for rotating a waveguide coupled with a high frequency to be fed as described in the above.
[0003]
On the other hand, in recent years, along with changes in lifestyle, there is an increasing tendency to use fresh prepared dishes and frozen preserved foods for daily menus. Therefore, there is a demand for a high-frequency heating device that can be cooked at a time and has good uniform heating properties.
[0004]
[Problems to be solved by the invention]
A method that can uniformly heat a large number of dishes at once is a stirrer method or a rotating waveguide method. The reason is that, unlike the turntable method, the food does not rotate and moves, so that the food can be filled to the bottom of the heating chamber (mostly a rectangular parallelepiped).
[0005]
In general, the rotating waveguide system having better stirring ability and better uniform heating performance than the stirrer system has the following problems. When heating food, the rotating waveguide is rotated in the heating chamber at a constant speed by a driving means such as a motor. However, since a rotating waveguide with strong directivity is used, the rotating waveguide is installed in front of the heating chamber. Naturally, the electric field in the vicinity of the door increases when facing the door side, and when the load is small, food tends to spark between the metal part of the door and the heating chamber when the load is light, and the resin part of the door increases with the electric field. There was a problem that the resin was heated to melt the resin.
[0006]
The present invention solves the above-mentioned conventional problems, and the high-frequency heating excellent in safety does not cause sparking of the door part and resin melting of the door part even at light loads when the food to be heated in the rotating waveguide system is small. An object is to provide an apparatus.
[0007]
[Means for Solving the Problems]
In order to solve the above-described conventional problems, a high-frequency heating device according to the present invention includes a heating chamber for storing an object to be heated, a door installed at an opening of the heating chamber, and an inverted truncated cone provided on the bottom surface of the heating chamber. And a radio wave radiating means having directivity provided in the throttle part. The radio wave radiating means is composed of a rotating waveguide, and the rotation center of the rotating waveguide is the center of the frustoconical diaphragm portion. The configuration is more biased toward the door side.
[0008]
Since the rotation center of the rotating waveguide is deviated from the center of the frustoconical diaphragm portion toward the door, when the rotating waveguide is facing the door, the tapered portion of the rotating waveguide and the truncated cone portion And the high-frequency radiation resistance increases. Therefore, the high frequency radiated into the heating chamber is reduced, and the electric field strength near the door is weakened. As a result, the spark around the door and the melting of the door resin parts are eliminated even when the food to be heated is light and the load is light. Conversely, when the rotating waveguide is facing away from the door, the distance between the rotating waveguide and the tapered portion of the truncated cone is large, so the high-frequency radiation resistance is small and the high-frequency output radiated into the heating chamber Becomes larger and the food is heated faster. As described above, according to the configuration of the present invention, without reducing the heating speed of the food in the rotating waveguide system, the safety of the spark of the door portion and the resin melting of the door portion does not occur even at a light load when the food to be heated is small. An excellent high-frequency heating device can be provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is a heating chamber for storing an object to be heated, a door installed at an opening of the heating chamber, an inverted frustoconical throttle provided at the bottom of the heating chamber, a radio wave radiating means having directivity provided to the aperture portion, a front Symbol radio emission means and radio-specifically bound excitation portion, a driving means for rotationally driving said radio wave emitting means, said radio wave emitting means is rotated guide The center of rotation of the rotating waveguide is biased toward the door side from the center of the truncated conical diaphragm portion. Since the rotation center of the rotating waveguide is biased to the door side from the center of the truncated cone-shaped aperture, the taper between the rotating waveguide and the truncated cone when the rotating waveguide faces the door. The distance to the part is small and the high-frequency radiation resistance is large. Therefore, the high frequency radiated into the heating chamber is reduced, and the electric field strength near the door is weakened. As a result, the spark around the door and the melting of the door resin parts are eliminated even when the food to be heated is light and the load is light. Conversely, when the rotating waveguide is facing away from the door, the distance between the rotating waveguide and the tapered portion of the truncated cone is large, so the high-frequency radiation resistance is small and the high-frequency output radiated into the heating chamber Becomes larger and the food is heated faster. As described above, according to the configuration of the present invention, without reducing the heating speed of the food in the rotating waveguide system, the safety of the spark of the door portion and the resin melting of the door portion does not occur even at a light load when the food to be heated is small. An excellent high-frequency heating device can be provided.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
(Example 1)
FIG. 1A is a plan view of the bottom surface of the heating chamber of the high-frequency heating device according to the first embodiment of the present invention, and FIG. 1B is a case where the rotating waveguide of the high-frequency heating device faces the door. 1A is a cross-sectional view taken along the line AA ′ in FIG. 1A, and FIG. 1C is a cross-sectional view taken along the line AA ′ in FIG. 1A when the rotating waveguide of the same high-frequency heating device is opposite to the door direction. It is sectional drawing. 1 (a), 1 (b), and 1 (c), the heating chamber 1 has a thin sheet metal substantially rectangular parallelepiped shape, and a door 2 for taking in and out food is installed in the opening. In the vicinity of the center of the bottom surface 3, a truncated cone-shaped drawn portion 4 is formed by drawing, and the tapered portion 4a is about 45 degrees. The opening of the drawn portion 4 is a sealing made of a glass or ceramic material. Means 5 are provided and the periphery is fixed with a ceramic adhesive. A high-frequency excitation unit 6 for supplying power into the heating chamber 1 is provided at the center of the bottom surface of the throttle unit 4. A high frequency generated by a magnetron (not shown) is guided to the excitation unit 6 through the waveguide 7. A motor 8 as a driving means is attached to the lower side of the excitation unit 6 with its output shaft inserted into the waveguide 7.
[0012]
The rotating waveguide 9 which is a radio wave radiating means has a sheet-metal fan shape, and is fixed to the side wing portion 9b and the side wing portion 9b which are close to the bottom surface of the diaphragm portion 4 on the left and right sides of the fan. A pair of tetrafluoroethylene spacers 9c that slide on the bottom surface, a tail portion 9d that is also close to the bottom surface of the throttle portion 4 near the center of the fan, and a sheet metal drawing process that is fixed near the tail portion 9d of the top surface 9a. It consists of an antenna shaft 9e. The antenna shaft 9e passes through the excitation unit 6 and is inserted and fitted into the output shaft of the motor 8. The rotating waveguide 9 has a configuration in which high-frequency propagation in the direction is suppressed by the fan-shaped left and right side wing portions 9b and the tail wing portion 9d, and high-frequency waves are transmitted in the direction of the fan-shaped spreading portion. Therefore, in FIG. 1, it has directivity in the arrow B direction. The rotation center E point of the rotating waveguide does not coincide with the center F point of the frustoconical diaphragm portion, and the E point is deviated by T (mm) from the F point toward the door 2. As shown in FIG. 1B, the distance between the tapered portion 4a of the throttle portion 4 and the rotating waveguide upper surface 9a when the rotating waveguide 9 faces the door 2 is L1, and the rotating waveguide 9 When the distance between the tapered portion 4a of the throttle portion 4 and the upper surface 9a of the rotating waveguide when L faces in the direction opposite to the door 2 is L2, there is a relationship of L1 <L2. (In the embodiment, T: 30 mm, L1: 13 mm, and L2: 73 mm.)
The operation and action of the high-frequency heating device of the present invention configured as described above will be described below.
[0013]
When the food is heated, the rotating waveguide 9 is rotated at a constant speed by the motor 8, but in the conventional example, when the rotating waveguide 9 faces the door 2, the electric field near the door 2 becomes strong, and the vicinity of the door 2 In some cases, the spark and resin parts of the door 2 were melted.
[0014]
In this embodiment, the rotational center E point of the rotating waveguide 9 is offset by 30 mm toward the door 2 side from the center F point of the truncated cone-shaped diaphragm portion 4, so that the rotating waveguide 9 faces the door 2 direction. In some cases, the distance L1 between the rotating waveguide 9 and the tapered part 4a of the truncated cone part is 13 mm, and the high-frequency radiation resistance is considerably increased. (In the embodiment, the height of the rotating waveguide 9 is 15 mm, and it is known that the high-frequency radiation resistance suddenly increases below this value). Therefore, the high frequency radiated | emitted in the heating chamber 1 decreases, and the electric field strength of the door 2 vicinity becomes weak. As a result, the spark around the door 2 and the door resin parts are not melted even when the food to be heated is light and light. On the contrary, when the rotating waveguide 9 is directed in the opposite direction to the door 2, the distance L2 between the rotating waveguide 9 and the tapered portion 4a of the truncated cone is large, so that the high-frequency radiation resistance is small and radiated into the heating chamber. The high frequency output increases and the food is heated quickly. As described above, according to the configuration of the present invention, without reducing the heating speed of the food in the rotating waveguide system, the safety of the spark of the door portion and the resin melting of the door portion does not occur even at a light load when the food to be heated is small. An excellent high-frequency heating device can be provided.
[0015]
【The invention's effect】
As described above, according to the present invention, in the rotating waveguide system, the safety of the spark of the door portion and the resin melting of the door portion does not occur even when the food to be heated is light and the load is light, without reducing the food heating speed. It is possible to provide a high-frequency heating apparatus excellent in the above.
[Brief description of the drawings]
FIG. 1A is a plan view of the bottom surface of a heating chamber of a high-frequency heating device according to Embodiment 1 of the present invention. FIG. 1B is a diagram showing a case where a rotating waveguide of the high-frequency heating device faces a door. (C) AA 'sectional view in Fig. 1 (a) when the rotating waveguide of the same high-frequency heating device faces away from the door.
DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Door 4 Constriction part 6 Excitation part 8 Motor (drive means)
9 Rotating waveguide (radiation means)

Claims (1)

A heating chamber for storing an object to be heated, a door installed at the opening of the heating chamber, an inverted frustoconical throttle provided at the bottom of the heating chamber, and directivity provided in the throttle a radio wave emitting means, and the previous SL radio emission means and radio-specifically bound excitation portion, a driving means for rotationally driving said radio wave emitting means, said radio wave emitting means is the rotating together is constituted by the rotary waveguide A high-frequency heating apparatus configured to deviate a rotation center of a waveguide from a center of the truncated cone-shaped throttle portion toward a door.

Images